Abstract: Aquatic ecoregion of watershed can offer an important foundation for integrated management of water environmental and for changing the management objectives from water quality to aquatic eco-health. Based on the natural attributes of the spatial differentiation of ecological pattern in the Liaohe river basin at a large scale and the progress on ecological environment division in home and abroad, the correlations between the natural factors such as the ratio of annual precipitation to mean annual temperature (P/T), depth of runoff (RD), digital elevation model (DEM), NDVI, hydrological and geologic factors (RP), aquatic environment factors of river and aquatic organism index were analyzed by a canonical correlation analysis (CCA) method. DEM, RD, RP and NDVI were selected as the first level factors of aquatic ecology division, and then an index system and a technical method on aquatic ecoregion were established. The results indicate that it can be divided into 4 first level aquatic ecoregions in the Liaohe river basin, i.e. the mountain and hill area in the upper reaches of west Liaohe river located in the southeast of Daxing’anling and the north of Hebei province, the plain area in the middle and lower reaches of the west Liaohe river, the plain area in the middle of the Liaohe river, the mountain and hill area in the upper reaches of Liaohe-Taizihe river, respectively. All the aquatic ecoregions have the significant relationships with the results of fish species cluster analysis according to historical data and field investigation data. The study offers the technical support for ecological management in the Liaohe river basin and references for the establishment of the technical method of aquatic ecoregion at watershed scale in China.

Key words:  Liaohe river basin, Aquatic ecoregion, Index system, Division method